QSFP+ Interconnect Solution for 40 Gigabit Ethernet

The QSFP+ optical transceiver is the dominant transceiver form factor used for 40 Gigabit Ethernet applications. In the year of 2010, the IEEE standard 802.3ba released several 40-Gbps based solutions, including a 40GBASE-SR4 parallel optics solution for multimode fiber. Since then, several other 40G interfaces have been released, including 40GBASE-CSR4, which is similar to 40GBASE-SR4 but extends the distance capabilities.

As is know to all, two switches are connected by either transceiver modules or cables. For example, if you simply wanted to cable up two Nexus 3000s with 40GbE, the options are multi mode fiber or twinax copper. We’ll only cover the fiber throughout this post as that is where most of the questions are in recent years. So, since you are now using fiber, how do we connect these switches into the network? First, you need to insert the QSFP+ optic similar to how you would insert a fiber optic for standard 1G or 10G connectivity. For the Nexus 3000, only multi mode fiber is available, so the Cisco part number needed is QSFP-40G-CSR4. This is the equivalent of the GLC-LH-SMD or SFP-10G-SR, for 1G and 10G, respectively. The connector type for QSFP-40G-CSR4 is no longer LC, but is a MPO (multi-fiber push-on) connector.

It is worth noticing that cables for 40G Ethernet actually have 12 fiber strands internal to them to achieve 40GbE. Distance limitations are 100m using OM3 and 150m using OM4 fiber respectively. Because these cables are connected with MPO connectors, have 12 strands, and are ribbon cables for native 40GbE. They will not be able to leverage any of your existing fiber optic cable plant. So be prepared to home run these cable where needed throughout the data center.

However, you may not always need native 40GbE between two switches. Instead, you may opt to configure multiple 10GbE interfaces instead. In this case, the QSFP-40G-SR4 is still needed, but the cable selection is different with what was previously shown above and the ability to use current cable plants is possible. The cable required here would have an MPO connector on one end that would connect into the QSFP port and then “break out” into 4 individual fiber links on the other end. These breakout cables terminate with LC male connectors. I would like to call it MTP-LC harness cable. The application for this MTP-LC harness cable is to directly connect a QSFP+ port to (4) SFP+ ports. For most Data Center applications, the use of structured cabling is employed via MTP trunks and the use of patch panels.

This is great that they terminate with LC male connectors because this allows customers to leverage the current cable infrastructure assuming existing patch panels have LC interfaces and OM3/OM4 fiber is used throughout the data center. These breakout cables are also nice if you want to attach a northbound switch that only supports 10GbE interfaces. You can easily direct connect or jump through a panel in the data center to connect the Nexus 3000 via multiple 10GbE interfaces to a Nexus 7000 (or any other switch with 10GbE-only interfaces).

Accordingly, direct attach cables which are terminated with QSFP+ connector is an alternative in 40G connectivity. For instance, HP JG331A compatible QSFP+ to 4SFP+ direct attach copper cable is terminated with one QSFP+ connector on one end and four SFP+ connector on the other end.

40G QSFP+ cables can provide inexpensive and reliable 40G speed connections using either copper cables with distances reaching up to 30ft (10 meters length) or active optical cables reaching even 300ft (100 meters). Cost of local NOC connectivity is significantly reduced by avoiding the more costly fiber transceivers and optical cables.

Guide to High-Speed Copper Transceivers

The last few decades have seen the broad adoption of fiber optic transceivers used in optical communications for both telecommunication and data communications applications. However, would the copper connectivity withdraw from the market? Copper medium usually doesn’t require any transceivers, as they are part of the interface module. However, in order to cut down expenditures, some vendors use SFP copper transceiver with an RJ-45 female connector for Gigabit Ethernet connectivity over copper medium, or XFP copper transceiver for 10Gigabit Ethernet (10GbE) connectivity over CX4 copper. This article will give you a complete guide to these copper transceivers.

Supporting 10/100/1000 Mbps data-rate in excess of 100 meters (325 feet) reach over UTP Category5/5e cables, copper transceiver module is ideally suited for implementing small form-factor Network Interface Cards (NICs) and uplinks. As such, it is highly appropriate for use in high-density applications such as LAN 1000BASE-T, switch-to-switch interfaces, switched backplanes, blade servers, gaming devices, and router/server interfaces.

With the development of 1000BASE-T technology, 1000BASE-T and 100BASE-TX copper SFP transceiver over Category 5 copper cabling is an attractive option for network. The advantages are listed as follows:

• For 100m reach over Cat 5 UTP cable
• Hot-pluggable SFP footprint
• Supports RX_LOS as link indication function
• Fully metallic enclosure for low EMI
• Low power dissipation (1.05 W typical)
• Compact RJ-45 connector assembly
• Compliant with SFP MSA and IEEE Std 802.3-2002

Here are two good examples of 1000BASE-T copper SFP transceivers, the Finisar FCLF-8521-3 compatible 1000BASE-T SFP copper transceiver and HP J8177C compatible 1000BASE-T SFP copper transceiver from FS.COM. Both of them are designed for 100m reach over Cat 5 UTP cable with RJ-45 interface and support max data rate of 1000Mbps.

As a kind of copper XFP transceiver, the XFP 10GBASE-CX4 module uses a CX4 connector to provide a connection to up to 15 meters over CX4 grade copper cable. Transparently to the user, the module transfers the 10GbE data stream over four full-duplex 3.125 Gbps channels over a single parallel copper cable. The product offers the ability to scale bandwidth in 10G increments, and directly with the industry standard MDI electrical socket.

CX4 is an extension of the four-channel 10 Gbps XAUI interface and is available in 70-pin MSA transponder modules, otherwise known as Xenpak, XPAK and X2. The 10GBASE-CX4 solution employs an Infiniband-style Twin-AX cable (click to see the Cisco 10G twinax). In this case, eight 100-ohm differential Twin-AX cables are bundled into a single outer shield. The center conductors are 24 AWG wire for compatibility with printed circuit board termination inside the connector housing. The limitation of the 10GBASE-CX4 solution is that it requires a 70-pin MSA socket and only supports the IEEE802.3ae 10GE data format.

The XFP format also offers the distinct feature of being data agnostic, which opens the market for the copper based solution to telecommunications applications as well. The 10 Gbps serial solution over copper adds the final link option to the XFP industry, offering everything from the ultra low-cost sub-20m 10 Gbps shelf-to-shelf and rack-to-rack links to 80 km or longer optical links.

Among the above-mentioned copper transceivers, what must be noticed is that copper SFP transceiver offers a flexible and simple method to be installed into SFP MSA compliant ports at any time with no interruption of the host equipment operation. It enables for seamless integration of fiber with copper LAN connections wherever SFP interface slots can be found. Such system is economical, it saves time, offers flexibility and eliminates the necessity for replacing entire devices once the customers have to change or upgrade fiber connections and you will benefit so much from it.

3 Ways Third-Party Transceivers Benefit Your Data Center

Are you still spending hundreds of dollars on the expensive optical transceiver modules for your network system in the data center? In order to cut down the costs on the expensive transceiver modules, many companies are seeking for a compatible third-party transceiver to use. For example, if your network contains Juniper routers, firewalls, and switches, you might think that only Juniper SFP branded transceivers will ensure that all of your equipment is compatible and functions optimally. However, that seemingly reasonable assumption could cost your company thousands of dollars. Compared to the third-party optical transceiver produced by third-party companies, Juniper SFP transceiver comes with dramatically inflated price tags while a third-party compatible one is roughly 80 percent less expensive than Juniper branded SFP transceiver.

What Does "Third-Party" Mean?

In commerce, a "third-party" means a supplier (or service provider) who is not directly controlled by either the seller (first party) or the customer/buyer (second party) in a business transaction. For example, in the fiber optics industry, all fiber optic transceivers are defined by Multi-Source Agreement (MSA). MSAs strictly define the operating characteristics of fiber optic networking equipment, so that system vendors may implement ports in their devices that allow MSA compliant networking components produced by different manufacturers are interoperable. As long as a manufacturer complies to MSA guidelines, their transceiver modules will function and operate identically to any other manufacturer's MSA-compliant transceivers. For instance, HP BladeSystem 455883-B21 compatible 10GBASE-SR SFP+ transceiver from FS.COM will function identically to a HP 455883-B21 transceiver and will be 100% compatible with HP networking equipment.  

Optical transceivers are some of the most all-around useful pieces of hardware for a network. As long as your equipment has SFP/SFP+ ports -which most do- transceivers allow you to change between a multitude of uplink types, to fit whatever wiring you have or will have in the future. They're simple, plug-and-play, and hot-swappable. Third-party optical transceivers can easily prevent thousands of dollars in new hardware costs. In spite of what's often implied by official documentation, a quality third-party optical transceiver is 100% compatible with name-brand equipment. There's simply no difference between good quality third-party transceivers and branded ones. So why choose to pay more?

Three Reasons Why Third-Party Optical Transceivers Just Make Sense

1. Low costs
The lower costs of third-party optics really cannot be overstated. Depending on the model, name brands are anywhere from 50% to 1000% more expensive than third-party alternatives. For example, you can get the Cisco QSFP-40G-CSR4 compatible 40GBASE-CSR4 QSFP+ transceiver with only $110 at FS.COM which ensures the same performance with a Cisco branded QSFP-40G-CSR4 transceiver.  

In many cases, a full loadout of third-party transceivers can shave so much money off of an upgrade budget to fund entirely new pieces of hardware. Or they can put a piece of equipment within range, which wouldn't have been if name-brand ports had to be purchased.

2. Full standards compliance
Only a few factories in the world produce optics, and they make the transceivers for everyone. Those heavily-discounted third-party may be made in the same facilities as the official Cisco, HP, or Juniper units. And since transceivers are fully specified by internationally agreed-upon standards anyway, there's no risk of incompatibilities.

All it takes is code loaded on an EPROM -included in the transceiver- identifying it to your networking hardware and, basically, your equipment can't tell the difference.

3. Lifetime warranty
Besides having much higher prices, the name-brand transceivers also tend to have fairly short warranty periods. It's generally anywhere from a couple years, down to only 90 days. While failure is fairly rare, it's unfortunate that they have such short warranty periods, especially compared to the hardware they're used in.

However, when you buy third-party optics from FS.COM, you will get a full lifetime warranty. That's how certain we are that they truly are of quality equal or better to the name-brand units. As long as your transceivers are in use, they're covered under warranty.

Conclusion

If you're still hesitant about trying a compatible SFP transceiver from a third party manufacturer, the best way to ensure that you're getting a reliable product at a good deal is to choose a vendor you trust, one with a proven track record of quality products and great customer service. Really, there's no compelling reason to over-pay for the name brand optics. Just like buying generic medications at the pharmacy, there is truly no difference aside from the name that's on the packaging.